We have made significant progress during the past fiscal year in our project. We one manuscript in a high quality journal (Ward et al, Science Translational Medicine, 2017) describing new clinical and pathological phenotypes related to lysosomal dysfunction in individuals with GRN mutations. A second manuscript describing our new method to generate large quantities of neurons from human stem cells was recently accepted (Wang & Ward et al, Stem Cell Reports). We have developed new proteomic methods to identify and quantify changes to the protein composition within lysosomes and interactions of lysosomes with other organelles and cytosolic proteins. Using these tools in stem cell derived neurons that lack progranulin, we have identified several networks of proteins that exhibit reduced recruitment to lysosomes in the setting of progranulin deficiency. We are in the process of investigating these hits with hypothesis-driven experiments in collaboration with Dr. Jennifer Lippincott-Schwartz at Janelia. Additionally, we have expanded our research team to enhance our ability to perform cutting-edge proteomic analysis of stem cell neurons by recruiting a post-doctoral fellow with expertise in mass spectrometry. Finally, we are exploring the possibility of using our stem cell derived neuronal models of neurodegenerative diseases for ultra-high throughput drug screens to identify new small molecule regulators of cell survival and abnormal phenotypes, in conjunction with NCATS.